Do NOT spray your grapes with any sulfur compounds within a month of harvest.

YEAST NUTRIENTS help prevent hydrogen sulfide problems.  Feed your yeast vitamins and nitrogen.  Research is showing that vitamins and other ingredients in complex nutrients, such as Fermaid, may be more important than just nitrogen.  DAP, diammonium nitrate, is just nitrogen.  

Try avoiding Red Star Montrachet.  (Sorry) and yet this yeast is very popular, so if you use it, feed it a complex nutrient.

Red Star Cotes des Blanc and Lalvin D-47 need to be fed.  Research your yeast nutrient requirements. 

Certain grape varieties need more nutrient, such as Chardonnay and Seyval.  Feed them or use a yeast (such as Lalvin QA 23) that has lower nutrient requirements. 

Ferment at moderate temperatures.

Use Potassium Metabisulfite per label and not excessively.  A level teaspoon is not heaping...

Smell your fermenting wine frequently!  If you detect a problem, rack off lees immediately, allowing the wine to aerate and splash about.  If the smell hasn't disappeared in 24 hours, rack again, allowing aeration and splashing. You may bubble an inert gas through the wine, carbon dioxide or nitrogen.

Try dosing with Reduless. 

If that fails, try copper sulfate.

WINEMAKERS ALERT: (We get this sort of recommendation every year!)
It has been brought to our attention through Cornell Co-op Extension that nutrient (nitrogen) levels in grapes and other fruits are very LOW. Make sure you USE YEAST NUTRIENT, Fermaid K OR DAP THIS YEAR. Here is a cut of a newsletter from Thomas Henick-Kling from the Geneva Experiment Station.

"Yeast available nitrogen content is low...   

This is to remind you that the available nitrogen content for yeast in grape must is again low this year. We have seen primary amino acid content of as low as 90 mg/L. For a good fermentation -without nutrient stress - the yeast should have approximately 400 mg/L of yeast available nitrogen. Please remember to make DAP and Fermaid and other yeast nutrient additions.  

Better to intervene early than having to correct off-odors later!  

I also noted in several of our fermentations that reduced sulfur odors had developed already in the first 3 to 5 days of fermentation. In such cases, the addition of 0.2 to 0.5 g/L of DAP or 0.2 g/L Fermaid in most cases corrects the off-odor. With the addition of the nitrogen (and vitamins) the yeast can re-metabolize the sulfur compounds and thus remove the off-odor. This is certainly the preferred way rather than correcting reduced sulfur off-odors later with additions of copper."   end of this newsletter, I can not remember the year.

Fall Bright stocks DAP (diammonium phosphate) and Fermaid K.

PLEASE, use label recommendations. DAP is labeled for use at 1/2 pound or 8 ounces per 1000 gallons. For the amateur winemaker, that translates to 1.13 grams per 5 gallons. Due to the differences in densities of DAP from different companies, weigh it.  If you have no gram scales, 1.13 grams is about 1/4 heaping teaspoon (per 5 gallons).  I think, we see rates all over the place all over the web.

Yeast "Energizer" is a term indicates a nutrient that is more complex and is recommended for fruit wines other than grapes and yet would be acceptable to use in grapes.

We currently are using Fermaid K, non-Kosher, which is also a complex nutrient (energizer). It is recommended for use with fruits other than grapes in winemaking. .

It has come to our attention that certain yeast, such as Cotes des Blanc, prefer the more varied components of a more complex yeast nutrient and can stall with just the DAP nutrient. Lalvin D-47 yeast also needs to be "fed"! So give it the best!

The overuse of a nutrient may render your wine too "hot" of an environment for the yeast to function in. So follow recommendations.

Fall Bright Usage Conclusions for Fermaid: 4 1/2 grams per 5 gallons. Dissolve in water before adding to an active fermentation to reduce foaming. 1 level teaspoon is ~4 1/2 grams. It is recommended to split the dose. The first 1/2 dose should be added at the end of the lag stage, which is just before fermentation starts. The second 1/2 of the dose should be added at 50% sugar depletion.

Do not double dose or add in addition to DAP.

Go-Ferm (Lalvin) is a micro nutrient for the yeast re-hydration process. It is not a nutrient to put in the juice.

Our juices and some grapes have been refrigerated. Let them come up to room temperature before inoculation.